


Beneath the Surface

by tatterwitch



Category: Voltron: Legendary Defender
Genre: Alternate Universe - Merpeople, Established Relationship, Octo-Boy Keith, Oviposition, Sailor Shiro, Size Kink, Tentacle Sex, Tentacles, Teratophilia
Language: English
Status: Completed
Published: 2018-03-24
Updated: 2018-03-24
Packaged: 2019-04-07 08:22:45
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 1,595
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/14076831
Author URL: https://archiveofourown.org/users/tatterwitch/pseuds/tatterwitch
Summary: “Shiro,” Keith’s voice rasped in the quiet of the seaside cave.Water dripped steadily from the spears of rock and mineral that hung from the lofty ceiling. Thick clumps of some kind of luminescent growth cast the space in a soft violet glow. Beneath the shivering surface of the pool, spanners of red pulsed along Keith’s tentacles.“Keith,” Shiro smiled.“Missed you.”Keith’s fingers carded through Shiro’s hair again, claws dragging lightly against his scalp. Tentacles tensed before slowly climbing higher on his thighs. Keith’s eyes lowered, leisurely taking their fill before flicking back up.“Want you.”





	Beneath the Surface

**Author's Note:**

> So.   
> Turns out that I'm not the only person in the Discord chat I'm in that's into some Kinky Shit. Shoutout to the ones who put me up to this; y'all know who you are.   
> It's currently 4:30AM, I haven't slept, yet. I have two shifts to work tomorrow. This is probably OOC. I apologize.

Water lapped at Shiro’s toes as he drew his clothes off.

 

The dampened fabric landed somewhere behind him. The exact whereabouts weren’t as interesting as the black tentacles that curled around his ankles and calves as he waded deeper.

 

The water was warm. It fizzed against Shiro’s skin and soothed the aches that had settled into his bones. It rose with the black limbs, over his knees, his hips, his waist…

 

Shiro ducked himself beneath the surface, scrubbing away the sticky layer of brine and sweat that coated his skin and hair. 

 

Another set of hands joined his own, raking over his scalp and tugging at the short strands there. Tentacles looped around his thighs and waist. A nose bumped against his own. Lips brushed over the corner of his mouth in an off-center kiss. 

 

Shiro kept his eyes shut against the salt water and leaned into the touch. His hands trailed down lithe arms and over parted gills. The latter touch earned him a near musical groan. Teeth nipped at his lower lip in reprimand...Or was it reward?

 

In either case, it made the last of Shiro’s air burn in his lungs.

 

The fingers in his hair tightened before sliding forward to cup his cheeks as his head broke the surface. Those fingers pushed his soaked hair back and swiped beneath his lashes as he caught his breath.

 

“Shiro,” Keith’s voice rasped in the quiet of the seaside cave.

 

Water dripped steadily from the spears of rock and mineral that hung from the lofty ceiling. Thick clumps of some kind of luminescent growth cast the space in a soft violet glow. Beneath the shivering surface of the pool, spanners of red pulsed along Keith’s tentacles. 

 

“Keith,” Shiro smiled.

 

“Missed you.” 

 

Keith’s fingers carded through Shiro’s hair again, claws dragging lightly against his scalp. Tentacles tensed before slowly climbing higher on his thighs. Keith’s eyes lowered, leisurely taking their fill before flicking back up. 

 

“Want you.” 

 

Shiro swallowed hard, heat pooling low in his belly. 

 

Keith’s limbs tightened, pulling him inexorably closer. Yet more trailed over his skin beneath the surface. Red flashed beneath the rippling water as Keith tipped his head up. His lower lip slipped free from between his teeth, dark and begging to be tasted. 

 

Shiro never had been able to resist Keith’s unspoken requests.

 

He closed the scant gap between them and swallowed the hungry noise Keith gave him. Claws pricked at his scalp when he nipped at Keith’s lip. 

 

The tentacles around Shiro’s legs inched higher. They wound around his thighs and curled around his hips. The undersides rippled, clinging to his skin with no small amount of strength. There’d be rows of delicate moon-shaped bruises banding his limbs in the morning.

 

Shiro’s hips bucked at the thought.

 

His reaction was not missed by Keith. 

 

More black limbs slid over Shiro’s body, exploring every inch of flesh in search of the spots that made Shiro weak. They slithered over his belly and along his chest, exploring with wet little popping noises that made Shiro’s mouth fall slack against Keith’s. They trailed past his hollowed belly and wriggling hips to tease all the spaces in-between. 

 

Keith broke their kiss with a rumbling sort of sigh and nipped at the edge of Shiro’s jaw. He lapped away the tiny sting.

 

Shiro canted his head back to allow Keith better access. Judging from the noise Keith made, it was a greatly-appreciated gesture. 

 

The very tips of needle-sharp teeth skated across his pulse. Shiro’s hips bucked again in search of touch, any touch, anywhere. 

 

Keith didn’t leave him wanting for long.

 

The set of tentacles on his hips slid back, undersides catching on the curves of his ass and parting him. Yet another pushed back, slipping over his hole. It teased him for only a moment before the very tip pressed inside.

 

Shiro gasped and rolled hip hips back in a bid for more. He felt Keith grin against his skin. The tentacle teased its way deeper in little pulses, slickness slowly coating his skin and insides. 

 

“More,” Shiro dipped his head, seeking out Keith’s mouth again.

 

Keith made a pleased little sound and acquiesced. He licked into Shiro’s mouth as another tentacle slid with the first and carefully slid alongside. They were thicker than Shiro’s fingers, longer and so gloriously textured. And still, it wasn’t enough.

 

“More,” Shiro whispered.

 

Another tentacle pressed in. It pushed deep, rubbing alongside the others before bumping against the spot that had Shiro’s hips rocking and a choked cry spilling from between his lips. 

 

“More,” Shiro pleaded, begged, implored.

 

He arched into every new touch, savoring the burn that crawled beneath his skin and settled hot and bright in his belly. 

 

Keith’s chest flushed dark. His eyes gleamed in the combined glow from the plants and his own bold luminescence. The dim lighting made the angles of his face seem so much sharper. Shadows pooled in the hollow beneath his throat. Water dripped from his tangled hair, trailing down over one cheek in a winding path that Shiro couldn’t help but follow with his lips. Keith turned his head at the last moment, catching Shiro’s mouth with his own. 

 

When Keith pulled back, his breath came harsh and shallow. The edges of his gills fluttered like he’d forgotten how to breathe above the surface. 

 

“Shiro-” Keith’s voice hitched, throat bobbing. “Want. Need-”

 

They’d talked about this earlier in Keith’s mating cycle. Keith’s kind carried a small clutch of eggs that either needed to be expelled as waste or laid within a partner. Keith had been adamant, maybe in not so many words, that he couldn’t ask the latter of Shiro. 

 

Shiro, though, had been...Intrigued. There was no chance for conception. And there was no reason for Keith to put himself through more discomfort. So Shiro had agreed. He’d do anything Keith needed him to do and more. 

 

Shiro pushed Keith’s hair back and nodded.

 

“Me, too.”

 

Something in Keith seemed to fray. His tentacles tightened around Shiro’s thighs and hips. His claws pricked at Shiro’s scalp before skating down to curl at his nape. Those violet-sky eyes hazed over, darkening as lashes swept down. Bruised lips parted over needle-sharp teeth. Achingly slowly, Shiro was left empty.

 

Then, something prodded between his legs.

 

Two somethings.

 

Rigid and swollen and much hotter than the other tentacles had been. One pressed against Shiro’s hole, slowly but inexorably entering him. 

 

_ Big _ . Shiro groaned, hips bucking and body arching. 

 

Keith’s teeth pressed against Shiro’s shoulder in a bid to still him. His tongue soothed over the tiny sting. 

 

Shiro’s mouth dropped open when Keith finally bottomed out. His thighs were held wide, wrapped tight in writhing black limbs that flickered with heady pulses of scarlet. He could feel just how exposed he was beneath the surface; how open and rawly vulnerable he was. Deep inside, he could feel Keith twitch and throb. His hips hitched uncontrollably. 

 

“Keith. Please, move.”

 

“Sure?” Keith’s voice was a dark, husky thing in his ear.

 

Shiro almost came then. He bit the inside of his cheek hard and nodded jerkily. 

 

Keith moved. His hips shifted the tiniest bit before the tentacle pushed in again. Pleasure burst, white-hot and blinding along Shiro’s nerves. He scrabbled for purchase, fingertips catching at Keith’s shoulders in a bid for leverage as his hips rocked into the next thrust.

 

Water splashed over the edges of the pool. It rolled over Shiro’s chest and spine as Keith bent him back. Teeth scraped over the base of his throat, the sting making him gasp.

 

Keith’s ragged cry echoed off of the wet walls of the cave as the first of the clutch left his body for Shiro’s. 

 

The egg slipped deep, settling heavily before Keith cried out again. And again.

 

The tentacle slid free, only to be replaced by the second. Shiro’s mouth dropped open as Keith began fucking into him in earnest. The eggs jostled with every thrust. 

 

Keith’s lips curled back from his teeth in a way that made Shiro’s heart lurch in his chest. The claws at the nape of his neck raked down across his shoulders and back. Scarlet flickered erratically along the edges of every writhing black limb. 

 

Keith’s snarl softened into an almost mournful ‘o’ as his whole body shuddered. 

 

_ Hot. Full _ . Shiro’s mind whited out.

 

* * *

 

 

Warm water lapped at Shiro’s chest. Clawed fingertips gently combed through his hair. Tentacles looped around his waist and hips in a light embrace. 

 

“Shiro,” Keith’s voice was soft and hoarse, barely audible over the sound of water running over rocks. 

 

“Mmm,” Shiro nuzzled into the palm that cupped his cheek. He didn’t want to move ever again. His whole body felt warm and heavy.

 

He must’ve said that out loud because Keith snorted and poked at his ribs.

 

“Tide.” Keith reminded him, voice a little melancholy.

 

Shiro sat up, heart dipping in his chest. He reached up, stroking a thumb over one still-flushed cheek. Keith leaned into the touch, eyes fluttering shut a little.

 

“I’ll be back in the morning. I promise.” 

 

Keith’s mouth curved up a little at one corner. He coiled his tentacles beneath his body and lifted his torso out of the water. 

 

Shiro stooped and pressed an off-center kiss to Keith’s lips. He snatched up his shirt and pulled it over his head hastily.

 

Keith sank back into the tidal pool, dark hair fanning out in the water. His gills fluttered beneath the surface. His lips moved silently, but Shiro understood.

 

“I love you, too, Keith.”

  
  



End file.
